JP7116595B2 - Tightening torque control tool and combination of tightening torque control tool and fastener - Google Patents

Description

The present invention relates to a tightening torque control tool for tightening a fastener such as a nut or bolt to a required torque, and a combination of such a tightening torque control tool and the fastener.

2. Description of the Related Art As is well known, bolts and nuts are used in large numbers in the installation of noise barriers on highways, the installation of ceiling walls in tunnels and the like, and the installation of various parts in various structures. In such fastening, a nut (usually a locking nut) is attached to the bolt, for example, in the case of a hexagonal nut with a nominal diameter of M10, it is about 17 to 24 Nm, and in the case of a hexagonal nut with a nominal diameter of M24, it is 250 Nm. It is important to tighten with a relatively high required torque, which is in the order of .about.360 Nm. Patent Literature 1 listed below discloses a tightening torque control tool that can be used when tightening a nut to a bolt or a bolt to a nut with a required torque. Such a tightening torque management tool is integrally formed from synthetic resin and includes a fastener housing portion and a tightening torque applying portion. The fastener housing portion is formed with a housing hole whose lower end face is open, and the inner peripheral surface of this housing hole is part of the regular polygonal inner peripheral surface corresponding to the torque-applying regular polygonal outer peripheral surface of the fastener. It is a form in which a concave portion is formed. The outer peripheral surface of the tightening torque applying portion corresponds to the outer peripheral surface of the torque applying regular polygon of the fastener. A fastener is at least partially housed in the housing hole of the fastener housing section, and a suitable manual or automatic tightener is engaged with the outer peripheral surface of the tightening torque application section to apply tightening torque, thereby applying the tightening torque. Tightening torque is transmitted to the fastener through the additional portion and the fastener storage portion. When the torque applied to the fastener exceeds a predetermined threshold value, the inner peripheral surface of the receiving hole is deformed, causing the fastener receiving portion to idle with respect to the fastener.

JP 2018-8352 A

Therefore, in the conventional tightening torque control tool as described above, especially when the threshold value of the torque to be managed is large, the thickness of each part of the tightening torque applying part as well as the thickness of each part of the fastener housing part is equivalent to the thickness of each part. It is necessary to set a large size, thus requiring a large amount of material for production, increasing production costs, and also being relatively difficult to avoid so-called sink marks, which tend to occur during molding, and A problem exists in that the cooling takes a relatively long time.

The present invention has been made in view of the above facts, and its main technical problem is to be able to avoid a large amount of necessary material even when the torque threshold to be managed is large, and also to be able to sufficiently To provide a new and improved tightening torque control tool integrally molded from synthetic resin, which can be easily manufactured, and also to provide a combination of such a tightening torque control tool and a fastener. .

As a result of extensive studies, the inventors of the present invention have found that instead of disposing the fastener storage portion and the tightening torque application portion separately, the outer peripheral surface of the portion itself that defines the storage hole for storing the fastener is It has been found that the above main technical problem can be achieved by improving the unique configuration that utilizes as a tightening torque applying portion.

That is, according to the first aspect of the present invention, as a tightening torque control tool for achieving the main technical problem described above, the inner part is integrally formed from a synthetic resin and defines a storage hole with an open lower end surface. It has a peripheral surface and an outer peripheral surface having a similar shape to the torque-applying polygonal outer peripheral surface of the fastener, and the inner peripheral surface defining the storage hole is a regular polygonal surface corresponding to the torque-applying regular polygonal outer peripheral surface of the fastener. A concave portion is formed on the square inner peripheral surface, and the bottom surface of the concave portion and the upstream surface located on the upstream side when viewed in the tightening rotation direction form an obtuse angle, and the fastener is stored in the storage hole. When tightening torque is applied to the outer peripheral surface of the fastener, if the tightening torque exceeds a threshold value, the inner peripheral surface of the storage hole is deformed and becomes idling with respect to the fastener. A tightening torque management tool is provided.
According to a second aspect of the present invention, there is provided a tightening torque control tool that achieves the main technical problem described above. and an outer peripheral surface having a similar shape to the torque-applying polygonal outer peripheral surface of the fastener, and the inner peripheral surface defining the storage hole is within a regular polygon corresponding to the torque-applying regular polygonal outer peripheral surface of the fastener A recess is formed in the central portion of each side surface of the peripheral surface, and a holding protrusion is formed in a portion of each side surface of the housing hole located upstream of the recess when viewed in the tightening rotation direction. When a fastener is housed in the housing hole and tightening torque is applied to the outer circumferential surface, when the tightening torque exceeds a threshold value, the inner circumferential surface of the housing hole is deformed to remove the fastener. There is provided a tightening torque management tool characterized by idling against.

Preferably, the inner peripheral surface has a form in which a concave portion is formed in the central portion of each side surface of the regular polygonal inner peripheral surface corresponding to the torque-applying regular polygonal outer peripheral surface of the fastener. In this case, each of the side surfaces of the housing hole is preferably parallel to each of the side surfaces of the outer peripheral surface of the main portion. It is preferable that a holding protrusion is disposed on a portion of each of the side surfaces of the above which is located upstream of the recess . A radially inwardly extending inner flange is preferably associated with the upper end. Advantageously, the inner peripheral surface of the inner flange portion is cylindrical. A radially outwardly extending outer flange is preferably associated with the lower end. The torque-applying regular polygonal outer peripheral surface of the fastener may be a regular hexagon. Preferably, the upstream surface of the recess extends outwardly at an angle in the tightening rotation direction .

Further in accordance with the present invention there is provided a combination of a tightening torque management tool as described above and a fastener at least partially received in the receiving hole of the tightening torque management tool. Preferably, the fastener is press fit into the receiving hole. The fastener may be a hex nut.

The tightening torque management tool of the present invention has a unique form in which the outer peripheral surface of the part itself defining the storage hole for storing the fastener is used as the tightening torque applying part, so when the torque threshold to be managed is large. However, the large amount of material required can be avoided, and also there is no need to separately form a portion of considerable thickness, which is therefore sufficiently easy to manufacture.

1 is a top perspective view of a preferred embodiment of a tightening torque management tool constructed in accordance with the present invention; FIG. FIG. 2 is an oblique view of the tightening torque management tool shown in FIG. 1 as seen from below; FIG. 2 is a front view partially showing a cross section of the tightening torque management tool shown in FIG. 1; FIG. 2 is a plan view of the tightening torque management tool shown in FIG. 1; FIG. 2 is a bottom view of the tightening torque management tool shown in FIG. 1; FIG. 2 is a front view partially showing a cross section of a combination of the tightening torque management tool shown in FIG. 1 and a nut, which is a typical example of a fastener; FIG. 7 is a cross-sectional view of the combination shown in FIG. 6; FIG. 7 is a cross-sectional view showing a state in which the tightening torque of the nut exceeds the threshold value and the tightening torque management tool idles with respect to the nut in the combination shown in FIG. 6 ;

A further detailed description will be made below with reference to the accompanying drawings showing a preferred embodiment of a tightening torque management device constructed in accordance with the present invention and a combination of such an embodiment with a nut, which is a typical example of a fastener.

1 to 3, the tightening torque control tool, generally indicated by number 2, is made of a suitable synthetic resin, preferably a relatively high-strength synthetic resin such as polycarbonate or acrylonitrile butadiene styrene (ABS); integrally formed by injection molding. The tightening torque control tool 2 has a cylindrical shape as a whole, and has an outer peripheral surface similar in shape to the inner peripheral surface 6 defining the storage hole 4 with the lower end face open and the outer peripheral surface of the torque-applying regular polygon of the tightening tool. 8.

4 and 5 together with FIGS. 1 to 3, the inner peripheral surface 6 defining the storage hole 4 is a virtual regular polygonal surface corresponding to the outer peripheral surface of a torque-applying regular polygon of the fastener to be stored. It is important that the concave portion 12 is formed on each side surface 10 of the square inner peripheral surface. In the illustrated embodiment, the fastener is a hexagonal nut, as will be described later, so that the torque-applying regular polygonal outer peripheral surface of the fastener is a regular hexagon, and the imaginary regular polygonal inner peripheral surface (indicated by a two-dot chain line in FIG. 5) inner peripheral surface shown) is also a regular hexagon. Each of the recesses 12 formed in the center of each side face 10 is located on both side faces together with the bottom face 12a. It has an upstream face 12b and a downstream face 12c. The angle α formed by the bottom surface 12a and the upstream surface 12b is an obtuse angle, preferably about 100 to 160 degrees. In the illustrated embodiment, the bottom surface 12a has an arc shape forming a part of a circle centered on the center of the housing hole 4, and the upstream surface 12b extends outwardly with respect to the side surface 10 in the tightening rotation direction. extends at an angle to the It is preferable that the bottom surface 12a and the upstream surface 12b are smoothly connected via an arc-shaped boundary surface 12d. On the other hand, the downstream surface 12 c extends perpendicularly to the side surface 10 . It is convenient that the circumferential length L1 of the side surface 10a on the downstream side of the recess 12 in the tightening rotation direction is longer than the circumferential length L2 of the side surface 10b on the upstream side of the recess 12 (in this case, , as will be clearly understood from the description below, the tightening torque threshold is defined by the deformation of the side surface 10a downstream of the recess 12).

A portion 10b located upstream of the recess 12 when viewed in the tightening rotation direction (clockwise direction in FIG. 4, counterclockwise direction in FIG. 5) on the side surface 10 defining the inner peripheral surface of the storage hole 4. is preferably provided with a retaining projection. In the illustrated embodiment, the retaining projection extends in the axial direction of the receiving hole 4 (vertically in FIG. 3 and perpendicular to the page in FIG. 5), preferably substantially parallel to the axis of the receiving hole 4. A rib 14 is formed. In the illustrated embodiment, a retaining projection or rib 14 is formed on each of the six side face 10 portions 10b. 2 and 3, each of the ribs 14 extends substantially parallel to the axis of the storage hole 4 from the upper end of the storage hole 4 to the vicinity of the lower end thereof. It is preferable that the protrusion height H of the rib 14 is about 0.1 to 0.5 mm, and the circumferential width W of each rib 14 is about 0.1 to 0.5 mm. Advantageously, the cross-sectional shape of the protruding end of rib 14 is semi-circular as shown in FIG. In the illustrated embodiment, ribs 14 are formed on all six side faces 10, portions 10b, but if desired, three side faces 10, e.g. It is also possible to form the ribs 14 only on the two side surfaces 10 that are aligned with each other.

The ribs 14 forming the holding protrusions are located not only on the portion 10b located on the upstream side of the recessed portion 12 when viewed in the tightening rotation direction on the side surface 10, but also on the downstream side of the recessed portion 12 when viewed on the side surface 10 in the tightening rotation direction. It can also be formed on the side portion 10a. However, if it is also formed in the portion 10a located downstream of the recess 12 as seen in the tightening rotation direction on the side surface 10, when the tightening torque reaches a threshold value as described later, the tightening rotation direction on the side surface 10 Since the portion 10a positioned on the downstream side of the recess 12 is mainly deformed as seen from the top, the rib 14 is deformed over its entirety prior to the deformation of the side surface 10, which causes the tightening torque to reach the threshold value. There is a tendency for the tightening torque management tool 2 to disengage from the fastener before it reaches. Therefore, it is desirable that the rib 14 is not provided on the portion 10a of the side surface 10 located downstream of the recess 12 when viewed in the tightening rotation direction.

As can be clearly understood by referring to FIG. 3, in the illustrated embodiment, an additional portion 16 having a circular inner peripheral surface is attached to the upper end of the receiving hole 4 . The inner peripheral surface of this additional portion 16 is positioned radially inwardly of the inner peripheral surface of the housing hole 4 (as will be further described later, the additional portion 16 has an annular shape formed on the upper surface of the locking nut). part is stored). Chamfering is applied to the lower end of the inner peripheral surface of the storage hole 4 .

Continuing with reference to FIGS. 1 to 5, the outer peripheral surface 8 is similar in shape to the torque applying polygon of the fastener as described above. In the illustrated embodiment, the fastener is a hexagonal nut, as will be described later, so that the outer peripheral surface 8 is a regular hexagon, which is about 1.2 to 1.6 times the regular hexagonal torque-applying regular polygon of the fastener. It is convenient to have Advantageously, each of the side surfaces 10 of the housing hole 4 and each of the side surfaces 18 of the outer peripheral surface 8 are parallel . As will be described later, when the torque applied to the outer peripheral surface 8 exceeds the threshold value while the fastener is stored in the storage hole 4, the inner peripheral surface 6 defining the storage hole 4 is deformed. In order to reliably avoid cracking across the face 8 and damaging the entire tightening torque control tool 2, diametrically opposed corners (side face 10 and side face 5) is preferably less than the length X2 (FIG. 4) between diametrically opposed side surfaces 18 of the outer circumferential surface 8. As shown in FIG.

In the illustrated embodiment, an inner flange portion 20 extending radially inward is formed at the upper end portion of the tightening torque management tool 2 . The main portion of the inner peripheral surface of the inner flange portion 20 has a cylindrical shape and the lower end portion has a truncated cone shape. A downwardly directed annular shoulder 22 is defined in the boundary area with the flange 20 . On the other hand, an outer flange portion 24 extending radially outward is formed at the lower end portion of the tightening torque control tool 2 . The outer peripheral surface of the outer flange 24 is cylindrical. The upper surface of the tightening torque management tool 2 (including the upper surface of the inner flange portion 20) may be a substantially horizontal plane, and similarly the lower surface of the tightening torque management tool 2 (including the lower surface of the outer flange portion 24) A horizontal plane is fine.

6 and 7 (in FIG. 7, a fastener, ie, a hexagonal nut 26 is press-fitted into the housing hole 4 to Although the ribs 14 are somewhat elastically or plastically deformed, such deformation is not shown and the ribs 14 are shown undeformed over the hex nut 26). It is convenient to circulate in In the embodiment shown in FIGS. 6 and 7, a locking hex nut 26 is shown as a typical fastener. The outer peripheral surface 28 of the hexagonal nut 26 is a regular hexagon, and if the manufacturing error of the hexagonal nut 26 is sufficiently small, it is slightly larger than the imaginary regular hexagon of the storage hole 8 formed in the fastener storage part 4 ( In other words, the imaginary regular hexagonal inner peripheral surface of the housing hole 4 in the tightening torque management tool 2 is set smaller than the regular hexagonal outer peripheral surface 28 of the hexagonal nut 26). Then, the main portion of the hexagonal nut 26 , that is, the portion other than the lower end portion is press-fitted into the housing hole 8 . An annular portion 30 formed on the upper surface of the hexagonal nut 26 is housed within the additional portion 16 and its upper edge abuts against the shoulder surface 22 . The hexagonal nut 26 has a portion 10a positioned downstream of the recess 12 as viewed in the tightening rotation direction (clockwise direction in FIG. 4 and counterclockwise direction in FIG. 5), and the ribs 14 are formed on the outer peripheral surface of the hexagonal nut 26. It is held in the receiving hole 4 by pressing against 28 . The manufacturing tolerance of the tightening torque control tool 2, which is injection-molded from an appropriate synthetic resin, is relatively small. has a relatively large manufacturing tolerance, and therefore the manufacturing error of the outer peripheral surface 28 of the hexagonal nut 26 is relatively large. This is compensated for by elastic or plastic deformation of ribs 14 formed on desired portions of the inner peripheral surface of the. Therefore, excessive or insufficient force required to press-fit the hexagonal bolt 26 into the housing hole 4 is avoided as much as possible.

To explain how to use the tightening torque management tool 2 as described above, when the hexagonal nut 26 is already combined with the tightening torque management tool 2, the shaft portion 32 of the bolt to which the hexagonal nut 26 is to be fastened (FIG. 6) (If the tightening torque control tool 2 is not combined with the hexagon nut 26, the hexagon nut 26 temporarily tightened to the bolt is stored in the storage hole 4 of the tightening torque control tool 2. ). Next, as indicated by the two-dot chain line in FIG. 6, the socket 34 of the automatic or manual tightening tool (the inner peripheral surface of the socket 34 has a hexagonal cylindrical shape corresponding to the outer peripheral surface of the tightening torque control tool 2) is tightened. It fits on the outer peripheral surface 8 of the torque control tool 2 . At this time, by bringing the lower end of the socket 34 into contact with the upper surface of the outer flange portion 24 of the tightening torque management tool 2, the socket 34 can be sufficiently easily positioned with respect to the tightening torque management tool 2 as required. be able to. Thereafter, the socket 34 of the fastener is rotated in the fastening direction (clockwise in FIG. 4 and counterclockwise in FIG. 5). The torque applied from the socket 34 to the tightening torque management tool 2 is transmitted to the hexagonal nut 26, thereby tightening the hexagonal nut 26 onto the shaft portion 32 of the bolt. When the hexagonal nut 26 advances over a relatively long distance in the axial direction with respect to the bolt shank 32, the bolt shank 32 is tightened as shown by the two-dot chain line in FIG. It penetrates the inner flange portion 20 of the torque control tool 2 and moves upward.

When the tightening torque transmitted to the square nut 26 exceeds a predetermined threshold value, as shown in FIG. is a portion downstream of the recess 12 of the upstream side surface 10 from the boundary area between the upstream side surface 10 and the downstream side surface 10 when viewed in the tightening rotation direction) is opposite to the tightening rotation direction The hexagonal nut 26 is pushed sideways and deformed, causing the tightening torque control tool 2 to idle against the hexagonal nut 26, thus tightening the hexagonal nut 26 to the bolt with the required tightening torque. When the tightening torque control tool 2 begins to idle with respect to the hexagonal nut 26, the corners of the outer peripheral surface of the hexagonal nut 26 may violently collide with the upstream surface 12b of the recess 12 of the housing hole 4. Since the bottom surface 12a and the upstream surface 12b of the portion 12 form an obtuse angle, the force applied to the upstream surface 12b of the recess 12 from the corners of the outer peripheral surface of the hexagonal nut 26 is appropriately buffered or eliminated. In addition, the socket 34 fitted on the outer peripheral surface 8 of the tightening torque management tool 2 functions as a reinforcing member for the tightening torque management tool 2 . Thus, generation of cracks in the tightening torque management tool 2 or breakage of the tightening torque management tool 2 is avoided as much as possible. After the tightening torque control tool 2 begins to idle with respect to the hexagonal nut 26, the bolt shaft 32 is tightened with the required tightening torque, and the tightening torque control tool 2 is sufficiently easily removed from the hexagonal nut 26. be able to.

In the embodiment described above, the retaining projection consists of a single rib 14 extending axially of the receiving hole 4, but if desired, axially or circumferentially spaced ribs 14 of the receiving hole 4 may be provided. a plurality of ribs extending in the circumferential direction of the housing hole 4, or a plurality of ribs extending in the circumferential direction at intervals in the axial direction or the circumferential direction of the housing hole 4, or a plurality of appropriately arranged ribs. It is also possible to form the retaining projections from projections (which are conveniently circular in cross-sectional shape).

2: tightening torque control tool 4: storage hole 6: inner peripheral surface 8: outer peripheral surface 10: side surface 12: recess 12a: bottom surface of recess 12b: upstream surface of recess 12c: downstream surface of recess 14: rib (holding projection part)
20: inner flange portion 24: outer flange portion 26: hexagonal nut 32: bolt shaft portion 34: fastener socket

Claims (13)

It is integrally formed from synthetic resin and has an inner peripheral surface that defines a storage hole with an open lower end surface and an outer peripheral surface that is similar in shape to the torque-applying polygonal outer peripheral surface of the fastener, and the storage hole The inner peripheral surface that defines the is a shape in which a concave portion is formed in the regular polygonal inner peripheral surface corresponding to the torque-applying regular polygonal outer peripheral surface of the fastener, and the bottom surface of the concave portion and the upstream side when viewed in the tightening rotation direction The upstream surface forms an obtuse angle, and when a fastener is stored in the storage hole and tightening torque is applied to the outer peripheral surface, when the tightening torque exceeds a threshold, the inner peripheral surface of the storage hole A tightening torque management tool characterized in that it is deformed and becomes idling with respect to the fastener. 2. The tightening torque management according to claim 1, wherein the inner peripheral surface has a form in which a concave portion is formed in the central portion of each side surface of the regular polygonal inner peripheral surface corresponding to the torque-applying regular polygonal outer peripheral surface of the fastener. equipment. 3. The tightening torque management tool according to claim 2, wherein each of said side surfaces of said receiving hole is parallel to each of said side surfaces of said outer peripheral surface. 4. The tightening torque management according to claim 2 or 3 , wherein a holding protrusion is disposed on a portion of each of the side surfaces of the housing hole that is positioned upstream of the recess when viewed in the tightening rotation direction. equipment. 5. The tightening torque management tool according to any one of claims 1 to 4 , wherein the upper end is provided with an inner flange extending radially inward. 6. The tightening torque management tool according to claim 5 , wherein the inner peripheral surface of the inner flange portion is cylindrical. 7. The tightening torque management tool according to any one of claims 1 to 6 , wherein the lower end is provided with an outer flange extending radially outward. 8. The tightening torque management tool according to any one of claims 1 to 7 , wherein the torque-applying regular polygonal outer peripheral surface of the tightening tool is a regular hexagon. 9. The tightening torque management tool according to any one of claims 1 to 8 , wherein the upstream surface of the recess extends outward at an angle in the tightening rotation direction. It is integrally formed from synthetic resin and has an inner peripheral surface that defines a storage hole with an open lower end surface and an outer peripheral surface that is similar in shape to the torque-applying polygonal outer peripheral surface of the fastener, and the storage hole The inner peripheral surface that defines is a shape in which a recess is formed in the center of each side surface of the regular polygonal inner peripheral surface corresponding to the torque-applying regular polygonal outer peripheral surface of the fastener, and when viewed in the tightening rotation direction A holding protrusion is disposed on each of the side surfaces of the housing hole in a portion located upstream of the recess, and a fastener is housed in the housing hole and a tightening torque is applied to the outer peripheral surface. A tightening torque management tool characterized in that when the tightening torque exceeds a threshold value, the inner peripheral surface of the receiving hole is deformed and becomes idling with respect to the fastener. 11. A combination of a tightening torque management device according to any one of claims 1 to 10 and a fastener at least partially housed in the housing hole of the tightening torque management device. 12. The combination of claim 11, wherein said fastener is press fit into said receiving hole. 13. A combination according to claim 11 or 12, wherein said fastener is a hex nut.

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